A common extension socket has a plurality of sockets, which provide alternate current to electric devices. Common electronic devices are usually disposed with a direct current adapter to lower the voltage of alternate current and to rectify it to alternate current, which is output to power electronic devices. However, for a direct current adapter, there is only one direct-current output plug for electronic devices. If alternate current is demanded for other electric devices, another extension with sockets is necessary to acquire alternate current. Therefore, it is not only inconvenient for users, but also hard to keep power cords organized.
Consequently, it is necessary to design a novel socket with power supply to overcome the drawbacks described above.